Scaffolding is commonly constructed from lengths of steel or aluminum tubes interconnected to each other to form an open structural framework. The size and configuration of the structure depends on the application. The interconnection of the tubes is normally made by two right angle couplers (“double couplers”) which are joined together. One of these double couplers can interconnect two of the three tubes that will normally meet at a right angle crossing of a scaffold structure. A second double coupler is required to interconnect a third tube to the first two.
The couplers are normally locked to the tubes by one or more nut and bolt locking devices. However, such couplers suffer from disadvantages. Their fastening and unfastening is time consuming and is inconvenient in requiring use of a wrench. Additionally, two hands are normally required to hold the coupler during the initial stages of fastening and the nuts and bolts are often corroded, making it difficult to thread and tighten the nuts. Also, the locking device may be under or over tightened on the tubes, leading to slipping or thread stripping respectively, which may compromise the safety of the scaffold structure.